Arduino RX

// RX
#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
#include <printf.h>

RF24 radio(7, 8);

const uint64_t addr = 0x0a0c0a0c0aLL;
char msg[100];

void setup(){
  Serial.begin(9600);
  radio.begin();
  printf_begin();
  radio.openReadingPipe(1, addr);
  radio.startListening();
  radio.printDetails();
  delay(1000);
}

void loop(){
  if(radio.available()){
    radio.read(msg, sizeof(msg));
    Serial.println(msg);
  }
}